Utilities
*********

Sphinx provides utility classes and functions to develop extensions.


Base classes for components
===========================

These base classes are useful to allow your extensions to obtain
Sphinx components (e.g. "Config", "BuildEnvironment" and so on)
easily.

Note:

  The subclasses of them might not work with bare docutils because
  they are strongly coupled with Sphinx.

class sphinx.transforms.SphinxTransform(document, startnode=None)

   A base class of Transforms.

   Compared with "docutils.transforms.Transform", this class improves
   accessibility to Sphinx APIs.

   property app

      Reference to the "Sphinx" object.

   property config

      Reference to the "Config" object.

   property env

      Reference to the "BuildEnvironment" object.

class sphinx.transforms.post_transforms.SphinxPostTransform(document, startnode=None)

   A base class of post-transforms.

   Post transforms are invoked to modify the document to restructure
   it for outputting. They do resolving references, convert images,
   special transformation for each output formats and so on.  This
   class helps to implement these post transforms.

   apply(**kwargs) -> None

      Override to apply the transform to the document tree.

   is_supported() -> bool

      Check this transform working for current builder.

   run(**kwargs) -> None

      main method of post transforms.

      Subclasses should override this method instead of "apply()".

class sphinx.util.docutils.SphinxDirective(name, arguments, options, content, lineno, content_offset, block_text, state, state_machine)

   A base class for Sphinx directives.

   This class provides helper methods for Sphinx directives.

   Note:

     The subclasses of this class might not work with docutils. This
     class is strongly coupled with Sphinx.

   set_source_info(node: docutils.nodes.Node) -> None

      Set source and line number to the node.

   property config

      Reference to the "Config" object.

   property env

      Reference to the "BuildEnvironment" object.

class sphinx.util.docutils.SphinxRole

   A base class for Sphinx roles.

   This class provides helper methods for Sphinx roles.

   Note:

     The subclasses of this class might not work with docutils. This
     class is strongly coupled with Sphinx.

   property config

      Reference to the "Config" object.

   content = None

      A list of strings, the directive content for customization

   property env

      Reference to the "BuildEnvironment" object.

   inliner = None

      The "docutils.parsers.rst.states.Inliner" object.

   lineno = None

      The line number where the interpreted text begins.

   name = None

      The role name actually used in the document.

   options = None

      A dictionary of directive options for customization

   rawtext = None

      A string containing the entire interpreted text input.

   text = None

      The interpreted text content.

class sphinx.util.docutils.ReferenceRole

   A base class for reference roles.

   The reference roles can accpet "link title <target>" style as a
   text for the role.  The parsed result; link title and target will
   be stored to "self.title" and "self.target".

   has_explicit_title = None

      A boolean indicates the role has explicit title or not.

   target = None

      The link target for the interpreted text.

   title = None

      The link title for the interpreted text.

class sphinx.transforms.post_transforms.images.ImageConverter(*args, **kwargs)

   A base class for image converters.

   An image converter is kind of Docutils transform module.  It is
   used to convert image files which does not supported by builder to
   appropriate format for that builder.

   For example, "LaTeX builder" supports PDF, PNG and JPEG as image
   formats.  However it does not support SVG images. For such case, to
   use image converters allows to embed these unsupported images into
   the document.  One of image converters; sphinx.ext.imgconverter can
   convert a SVG image to PNG format using Imagemagick internally.

   There are three steps to make your custom image converter:

   1. Make a subclass of "ImageConverter" class

   2. Override "conversion_rules", "is_available()" and "convert()"

   3. Register your image converter to Sphinx using
      "Sphinx.add_post_transform()"

   convert(_from: str, _to: str) -> bool

      Convert a image file to expected format.

      *_from* is a path for source image file, and *_to* is a path for
      destination file.

   is_available() -> bool

      Return the image converter is available or not.

   conversion_rules = []

      A conversion rules the image converter supports. It is
      represented as a list of pair of source image format (mimetype)
      and destination one:

         conversion_rules = [
             ('image/svg+xml', 'image/png'),
             ('image/gif', 'image/png'),
             ('application/pdf', 'image/png'),
         ]


Utility components
==================

class sphinx.events.EventManager(app=None)

   Event manager for Sphinx.

   add(name)

      Register a custom Sphinx event.

   connect(name, callback)

      Connect a handler to specific event.

   disconnect(listener_id)

      Disconnect a handler.

   emit(name, *args)

      Emit a Sphinx event.

   emit_firstresult(name, *args)

      Emit a Sphinx event and returns first result.

      This returns the result of the first handler that doesn't return
      "None".
